Help me please! Write and solve an equation to show the sum of the interior angles of the triangle.
What is the value of the missing angles?

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).

240 seventh graders and two-thirds of the students participate in after-school activities how many students participate in after-school activities

Aplot of land in the shape of a vertical ellipse has a pole at each focus. the foci are 8 feet from the center. if the plot of land is 34 feet across the vertical axis, then it is (a.24 b. 30 c. 32 d. 36) feet across the other axis. the eccentricity of the ellipse traced by the boundary of this plot, rounded to the nearest thousandth, is (a.0.543 b.0.515 c.0.471 d. 0.459)